Power Management

ACPI

Also add acpid to the DAEMONS line in you /etc/rc.conf (note that this is not necessary if you already have hal in there since acpid has been added to its starting script).

I found out that when booted with ACPI on, the laptop makes kind of high frequency noise which can be really annoying when you work in otherwise quiet room. There is no such noise when you boot with acpi=off. I searched for a solution and I found this:

Pass this to the kernel by changing your /boot/grub/menu.lst (the whole entry should look something like this):